util.go

package main

import (
	"math"
	"strconv"
	"strings"
	"unicode"
)

// Trims the last decimals up to maxDecimals, does nothing if maxDecimals is less than 0, e.g -1
func trimLastDecimals(numberString string, maxDecimals int) string {
	if maxDecimals < 0 {
		return numberString
	}

	dotIndex := strings.Index(numberString, ".")
	if dotIndex == -1 {
		return numberString
	}

	return numberString[:min(len(numberString), dotIndex+maxDecimals+1)]
}

// If maxDecimals is less than 0, e.g -1, we show the exact size down to the byte
// https://en.wikipedia.org/wiki/Byte#Multiple-byte_units
func BytesToHumanReadableUnitString(bytes uint64, maxDecimals int) string {
	unitValues := []float64{
		math.Pow(10, 3),
		math.Pow(10, 6),
		math.Pow(10, 9),
		math.Pow(10, 12),
		math.Pow(10, 15),
		math.Pow(10, 18), // Largest unit that fits in 64 bits
	}

	unitStrings := []string{
		"kB",
		"MB",
		"GB",
		"TB",
		"PB",
		"EB",
	}

	if bytes < uint64(unitValues[0]) {
		return strconv.FormatUint(bytes, 10) + " B"
	}

	for i, v := range unitValues {
		if bytes >= uint64(v) {
			continue
		}

		lastIndex := max(0, i-1)
		return trimLastDecimals(strconv.FormatFloat(float64(bytes)/unitValues[lastIndex], 'f', -1, 64), maxDecimals) + " " + unitStrings[lastIndex]
	}

	return trimLastDecimals(strconv.FormatFloat(float64(bytes)/unitValues[len(unitValues)-1], 'f', -1, 64), maxDecimals) + " " + unitStrings[len(unitStrings)-1]
}

// Looping over the entire invisibleRunes array in isInvisible() showed up pretty high when profiling with pprof, so we generate a list of (start,end) ranges to check instead
// {9,13, 32,32, ..., 6155 6158, ..., 917760 917999}
func getInvisibleRunesAsRanges() []uint64 {
	var ret []uint64
	var lastRuneCode uint64

	// Invisible or blank runes like space
	// From https://github.com/flopp/invisible-characters/blob/main/main.go#L63 (Downloaded 2024-06-11 16:52 norway time, commit 0f7fc8a)
	var invisibleRunes = [...]uint64{9, 10, 11, 12, 13, 32, 127, 160, 173, 847, 1564, 4447, 4448, 6068, 6069, 6155, 6156, 6157, 6158, 7355, 7356, 8192, 8193, 8194, 8195, 8196, 8197, 8198, 8199, 8200, 8201, 8202, 8203, 8204, 8205, 8206, 8207, 8234, 8235, 8236, 8237, 8238, 8239, 8287, 8288, 8289, 8290, 8291, 8292, 8293, 8294, 8295, 8296, 8297, 8298, 8299, 8300, 8301, 8302, 8303, 10240, 12288, 12644, 65024, 65025, 65026, 65027, 65028, 65029, 65030, 65031, 65032, 65033, 65034, 65035, 65036, 65037, 65038, 65039, 65279, 65440, 65520, 65521, 65522, 65523, 65524, 65525, 65526, 65527, 65528, 65532, 78844, 119155, 119156, 119157, 119158, 119159, 119160, 119161, 119162, 917504, 917505, 917506, 917507, 917508, 917509, 917510, 917511, 917512, 917513, 917514, 917515, 917516, 917517, 917518, 917519, 917520, 917521, 917522, 917523, 917524, 917525, 917526, 917527, 917528, 917529, 917530, 917531, 917532, 917533, 917534, 917535, 917536, 917537, 917538, 917539, 917540, 917541, 917542, 917543, 917544, 917545, 917546, 917547, 917548, 917549, 917550, 917551, 917552, 917553, 917554, 917555, 917556, 917557, 917558, 917559, 917560, 917561, 917562, 917563, 917564, 917565, 917566, 917567, 917568, 917569, 917570, 917571, 917572, 917573, 917574, 917575, 917576, 917577, 917578, 917579, 917580, 917581, 917582, 917583, 917584, 917585, 917586, 917587, 917588, 917589, 917590, 917591, 917592, 917593, 917594, 917595, 917596, 917597, 917598, 917599, 917600, 917601, 917602, 917603, 917604, 917605, 917606, 917607, 917608, 917609, 917610, 917611, 917612, 917613, 917614, 917615, 917616, 917617, 917618, 917619, 917620, 917621, 917622, 917623, 917624, 917625, 917626, 917627, 917628, 917629, 917630, 917631, 917760, 917761, 917762, 917763, 917764, 917765, 917766, 917767, 917768, 917769, 917770, 917771, 917772, 917773, 917774, 917775, 917776, 917777, 917778, 917779, 917780, 917781, 917782, 917783, 917784, 917785, 917786, 917787, 917788, 917789, 917790, 917791, 917792, 917793, 917794, 917795, 917796, 917797, 917798, 917799, 917800, 917801, 917802, 917803, 917804, 917805, 917806, 917807, 917808, 917809, 917810, 917811, 917812, 917813, 917814, 917815, 917816, 917817, 917818, 917819, 917820, 917821, 917822, 917823, 917824, 917825, 917826, 917827, 917828, 917829, 917830, 917831, 917832, 917833, 917834, 917835, 917836, 917837, 917838, 917839, 917840, 917841, 917842, 917843, 917844, 917845, 917846, 917847, 917848, 917849, 917850, 917851, 917852, 917853, 917854, 917855, 917856, 917857, 917858, 917859, 917860, 917861, 917862, 917863, 917864, 917865, 917866, 917867, 917868, 917869, 917870, 917871, 917872, 917873, 917874, 917875, 917876, 917877, 917878, 917879, 917880, 917881, 917882, 917883, 917884, 917885, 917886, 917887, 917888, 917889, 917890, 917891, 917892, 917893, 917894, 917895, 917896, 917897, 917898, 917899, 917900, 917901, 917902, 917903, 917904, 917905, 917906, 917907, 917908, 917909, 917910, 917911, 917912, 917913, 917914, 917915, 917916, 917917, 917918, 917919, 917920, 917921, 917922, 917923, 917924, 917925, 917926, 917927, 917928, 917929, 917930, 917931, 917932, 917933, 917934, 917935, 917936, 917937, 917938, 917939, 917940, 917941, 917942, 917943, 917944, 917945, 917946, 917947, 917948, 917949, 917950, 917951, 917952, 917953, 917954, 917955, 917956, 917957, 917958, 917959, 917960, 917961, 917962, 917963, 917964, 917965, 917966, 917967, 917968, 917969, 917970, 917971, 917972, 917973, 917974, 917975, 917976, 917977, 917978, 917979, 917980, 917981, 917982, 917983, 917984, 917985, 917986, 917987, 917988, 917989, 917990, 917991, 917992, 917993, 917994, 917995, 917996, 917997, 917998, 917999}

	var start uint64
	length := uint64(1)
	for i, e := range invisibleRunes {
		if i == 0 {
			start = e
			lastRuneCode = e
			continue
		}

		if i == len(invisibleRunes)-1 {
			length++
		}

		if e-1 != lastRuneCode || i == len(invisibleRunes)-1 {
			ret = append(ret, start)
			ret = append(ret, start+length-1)
			length = 1
			start = e
		} else {
			length++
		}

		lastRuneCode = e
	}

	if len(ret)%2 != 0 {
		panic("getInvisibleRunesAsRanges failed to produce an even-numbered list")
	}

	return ret
}

var InvisibleRunesRanges = getInvisibleRunesAsRanges()

func isInvisible(c rune) bool {
	if !unicode.IsPrint(c) {
		return true
	}

	for i := 0; i < len(InvisibleRunesRanges); i += 2 {
		if c >= rune(InvisibleRunesRanges[i]) && c <= rune(InvisibleRunesRanges[i+1]) {
			return true
		}
	}

	return false
}

func RuneToPrintableCode(c rune) string {
	switch c {
	case '\a':
		return "\\a"
	case '\b':
		return "\\b"
	case '\f':
		return "\\f"
	case '\n':
		return "\\n"
	case '\r':
		return "\\r"
	case '\t':
		return "\\t"
	case '\v':
		return "\\v"
	}

	return "\\u" + strconv.FormatInt(int64(int32(c)), 16)
}

// Shows invisible runes as escape sequences like "\n", "\r", "\t", or "\u<HEX NUMBER>"
//
// Each of these will have a dark-red background, starting with "[:darkred]", and ending with "[-:-:-:-]"+defaultStyle which sets the colors back to whatever is specified in the defaultStyle style tag string
//
// Spaces are shown as normal, except leading and trailing ones, which will be shown as "\u20"
func FilenameInvisibleCharactersAsCodeHighlighted(filename, defaultStyle string) string {
	if filename == "" {
		panic("FilenameInvisibleCharactersAsCodeHighlighted got empty filename")
	}

	leadingInvisibleOrNonPrintableCharLength := 0
	for _, c := range filename {
		if isInvisible(c) {
			leadingInvisibleOrNonPrintableCharLength++
		} else {
			break
		}
	}

	trailingInvisibleOrNonPrintableCharLength := 0
	filenameRunes := []rune(filename)
	for i := len(filenameRunes) - 1; i >= leadingInvisibleOrNonPrintableCharLength; i-- {
		c := filenameRunes[i]
		if isInvisible(c) {
			trailingInvisibleOrNonPrintableCharLength++
		} else {
			break
		}
	}

	var ret strings.Builder
	for i, c := range filename {
		// Use printable codes for leading and trailing invisible or non-printable runes
		if i < leadingInvisibleOrNonPrintableCharLength || len(filename)-i <= trailingInvisibleOrNonPrintableCharLength {
			ret.WriteString("[:darkred]" + RuneToPrintableCode(c) + "[-:-:-:-]" + defaultStyle)
			continue
		}

		// For the rest, don't use printable codes for space
		if c != ' ' && isInvisible(c) {
			ret.WriteString("[:darkred]" + RuneToPrintableCode(c) + "[-:-:-:-]" + defaultStyle)
			continue
		}

		ret.WriteRune(c)
	}
	return ret.String()
}